Acceleration and deceleration valve apparatus

ABSTRACT

Acceleration and deceleration valve apparatus having a housing body with a bore formed therein, a piston slidably inserted in the bore, a bias device for biasing the piston, a throttle device the opening of which is controlled by the piston, the piston dividing the bore into front and back chambers, an oil passage connecting the two chambers, a valve device provided in the oil passage, a pressure inlet for supplying oil to the oil passage, and an outlet for flowing out the oil through the throttle device.

United States Patent n91 Mito et al.

I ACCELERATION AND DECELERATION VALVE APPARATUS [75] Inventors: AkioMito, Yokohama; Masayasu Desaki, Tokyo; Kunio Koike,

Hayama-Machi; Shunji Kikui, Tokyo, all of Japan [73] AssigneesKabushikikaisha Tokyo Keiki,

Tokyo, Japan [22] Filed: Jan. 24, 1972 1211 Appl. No.: 220,319

[52] U.S. C1 251/15, 251/50, 137/501 [51] 1nt. C1. Fl6k 21/04 [58] Fieldof Search 251/15, 31, 50;

[56] References Cited UNITED STATES PATENTS Passaggio 251/15 X [451 Nov.6, 1973 9/1970 Cryder et a] 251/50 X 1/-,l9 7l Kihara et al. 137/501Primary ExaminerHenry T. Klinksiek Attorney-George B. Oujevolk [5 7]ABSTRACT Acceleration and deceleration valve apparatus having a housingbody with a bore formed therein, a piston slidably inserted in the bore,a bias device for biasing the piston, a throttle device the opening ofwhich is controlled by the piston, the piston dividing the bore intofront and back chambers, an oil passage connecting the two chambers, avalve device provided in theoil passage, a pressure inlet for supplyingoil to the oil passage, and an outlet for flowing out the oil throughthe throttle device.

12 Claims, 6 Drawing Figures 1 ACCELERATION AND DECELERATION VALVEAPPARATUS BACKGROUND OF THE-INVENTION 1. Field of the Invention Thepresent invention relates to an acceleration and deceleration valveapparatus for hydraulic position control and particularly to anacceleration and deceleration valve apparatus for hydraulic positioncontrol simple in construction and correct in operation.

2. Description of the Prior Art A conventional acceleration anddeceleration valve apparatus has the drawback that it is inaccurate inposition control.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is aschematic diagram in cross-section illustrating an example of thepresent invent-ion;

FIG. 2'is a cross-sectional schematic diagram showing another example ofthe present invention;

FIG. 3 is a schematicv diagram in cross-section as in FIG. 2 except thatthe valve device is opened;

FIG. 4 is a cross-sectional schematic diagram showing still anotherexample of thisinvention;

FIG. 5 is a cross-sectional schematic diagram as in FIG. 4 except thatthe valve device is opened; and

FIG. 6 is a graph used for explaining the operation of the exampledepicted in FIGS. 4 and 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 reference numeral 1generally designates an example of acceleration and deceleration valveappara tuses for hydraulic position control of this invention. Referencecharacter la shows the apparatus proper or a housing body of the valveapparatus 1. Reference numeral 4 represents a bore formed in the body laand reference numeral 6 a bore also formed in the body 1a. The bore 6issmaller than the bore 4 in inner diameter and connected to the latter.Reference numeral 3 designates a piston which is inserted into the bore4 and can be moved therein along a direction showed by an arrow a Thepiston 3 has provided with a projection 5 on its one side, namely on itsright hand side in the example of FIG. 1.'The diameter of the projection5 is smaller than that of the piston 3. The projection 5 has formed onits free end portion a tapered portion designates at 5a which can bemoved in the bore 6. Refer-- ence numerals l and 7 represent front andback oil the piston in the direction shown by an arrow'a namely in theleft hand direction in the figure. The projection 5 attached to thepiston 3 has formed therein an oil passage 9 one opening 9a of which isopened in the back chamber 7 while the other opening 9b of which isopened in an oil chamber 8 formed in the sliding bore 6. Referencenumeral 15 shows an annular groove formed in the body 1.: around thebore 6 at the position corresponding to the root of thetapered portion5a formed around the projection 5 when the piston 3 is positioned at theright hand end of the bore 4 against the spring force of the coiledspring 2. The annular groove 15- is connected to the bore 6 or the oilchamber 8 and forms a throttle device 16 in association with theprojection 5, especially with its tapered portion 5a.. The throttledevice 16 is controlled by the movement of the piston 3 in opening, 1

Reference numeral 19 represents a pressure supply source and referencenumeral '13 an pressure inlet formed in the body la which is connectedto the pressure oil supply source 19 through, for example, a pipe 19aand also toithe bore 4'at its front chamber 10 through an oil passage13a formed in the body la. Reference numeral 12 shows a throttle formedin the oil passage 13a and reference numeral 11 a check valve formed inan oil passage 13b which is formed in the body la parallel with the oilpassage 13a and through which the pressure inlet 13 is connected withthe front oil chamber 10 of the bore 10. Reference numeral 14 designatesa valve device such, for example, as a solenoid valve which connects thepressure inlet 13 with the oil chamber 80f the bore 6 through oilpassages 14a and 14b. The oil flowed into the oil chamber 8 through thesolenoid valve 14 returns to an oil tank 18 through the throttle device16 and an oil passage 17 formed in the body la and an oil passage 17a.

Inthe case where the solenoid valve 14 is closed as shown in the figure,the oil supplied to the pressure inlet 13 from the pressure supplysource 19 flows into the front chamber 10 through the check valve 11 toshift the piston 3 to the right hand direction in the figure against thecoiled spring 2. As a result, the projection 5 attached to the piston 3is also shifted to the right hand direction in the bore 6 of a smalldiameter to substantially close the throttle device 16, which will meansthat no oil flows through the throttle device 16. In this case thespring force of the coiled spring 2 is selected in such a manner thatwhen the solenoid valve 14 is opened and the rated oil flows through thesolenoid valve 14 into the oil chamber 8, the spring force of the coiledspring 2 is large enough as compared with the oil pressure exerting onthe piston 3 due to the inner pressure drop of the oil through thesolenoid valve 14.

When the solenoidvalve 14 is opened, when the pressure oil is fed to oneoil chamber of the hydraulic actuator(not shown) upon the accelerationsignal and the solenoid valve 14 is opened by connecting the outletchamber thereof to the acceleration and deceleration valve, the oilflows to the oil chamber 8 of the bore 6 from the pressure inlet 13through the oil passage 14a, the solenoid valve 14 and the oil passage14b and the oil flowed into the oil chamber 8 flows into the tank 18through the throttle device 16 which is opened little and the oilpassages 17 and 170. At this time the pressure difference between thefront and back oil chamhas 10 and 7 of the bore 4 divided by the piston3 is substantially equal to the inner pressure drop in the solenoidvalve 14. Thus, the piston 3 is moved to the left hand direction in thefigure by the spring force of the coiled spring 2. The moving speed ofthe piston 3 to the left is determined by the throttle 12 formed in theoil passage 13a. As the piston 3 is moved to the left, the opening ofthe throttle device 16 is increased gradually to increase the flow rateof the oil through the throttle device 16. When the piston 3 arrives atthe left hand end of the bore 4, the throttle device 16 is opened at itsmaximum. Thus, the piston of the hydraulic actuator can be moved at highspeed following to the acceleration motion. g

If the solenoid valve 14 is closed, i.e., if the piston of the hydraulicactuator (not shown) is moved to a predetermined position, thedeceleration signal is produced by, for example, a limit switch and thenthe solenoid valve 14 is closed, no oil flows through it. Accordingly,the oil pressure in the chamber 7 is decreased'to increase the pressuredifference of the oils between the front and back chambers and 7 overthe spring force of the coiled spring 2. As a result, the oil flows intothe chamber 10 through the check valve 11 to shift the piston 3 to theright. According to the movement of the piston 3 to the right, theopening degree of the throttle device 16 is decreased to decrease theflow rate of the pressure oil through the throttle device 16, by whichthe moving speed of the piston 3 to the right is made low. When thepiston 3 reaches the right end of the bore 4 at low speed, its movementis stopped. The flow rate an amount of the oil flowed into the frontchamber 10 during the movement of the piston 3 at decelerated speed tothe right is a constant value determined inaccordance with the amount ofthe moving volume of the piston 3. As set forth above, the decelerationoperation of the piston 3 is carried out with the oil of a constantvolume.

Accordingly, the deceleration distance of the piston of the hydraulicactuator (not shown) from the generation of the deceleration signalbecomes also constant.

Another example of this invention will be explained hereinbelow withreference to FIGS. 2 and 3 in which reference numerals same to those ofFIG. 1 show the same elements and their explanation will be omitted forthe sake of brevity because they are substantially same in constructionand operation.

In this example first and second check valves 21 and 22 are respectivelyprovided in the body 101a instead of the biasing means such. as thecoiled spring 2 in the example of FIG. 1. The first and second checkvalves 21 and 22 are both closed when the differential pressure is lowerthan a set value, while opened when the differential pressure is higherthan the set value. The first check valve 21 is located in the oilpassage 13a for connecting the pressure inlet 13 with the front chamber10, while the second check valve 22 is located in an oil passage 22aformed in the body 1a for connecting the back chamber 7 with an annularoil groove 26 formed in the body la around the bore 6 at the positionadjacent to the groove 15 and at the right side with respect to thelatter. Reference numeral 14e represents an oil passage which connectsan oil outlet 13' of the passage 13a connected to the pressure inlet 13with a first closed portion 14c of the solenoid valve 14, referencenumeral 14f an oil passage which connects a second closed portion 14d ofthe solenoid valve 14 with an oil passage 20 formed in the body 101a andconnected to the oil passage 22a and to the annular groove 26, referencenumeral 14g an oil passage which connects the first closed portion 14with an oil passage 28 formed in the body 1a and connected to the backoil chamber 7 and to the passage 22a, and reference numeral 14h an oilpassage which connects the second closed portion 14d with a branch oilpassage 27 formed in the body 101a and connected to the front chamber 10and to the oil passage 13a. The check valve 11 and the throttle 12 usedin FIG. 1 are omitted in this example. The flow direction of the oilthrough the first check valve 21 from the pressure supply source 19 isselected in such a manner that the oil flowed into the pressure inlet 13from the pressure supply source 19 passes to the front chamber 10through the first check valve 21, while the flow direction of the oilthrough the second check valve'22 is selected in such a manner that theoil flowed into the oil passage 28 flows through the second valve 22 tothe annular groove 26. Reference numeral 25 shows a top portion of adiameter substantially same to the inner diameter of the bore 6 which isattached to the free end of the projection 5. The oil passage 9 formedin the projection 5 passes through the top portion 25 and opens in thechamber 8 in the bore 6.

The solenoid valve 14 shown in FIG. 2 is closed, so that no oil passesthrough thesolenoid valve 14 at this condition. If the solenoid valve 14is opened as shown in FIG. 3, the oil supplied to the pressure inlet 13from the source 19 through the pipe 19a flows into the back chamber '7through the oil passage 14s, a first opened portion 140' and the oilpassages 14g and 28, while the oil in the front chamber 10 flows to theoil tank 18 through the oil passages 27, l4h, a second opened portion14d, the oil passages 14f, 20, the throttle device 16 and the oilpassages 17 and 170. In this case the preliminary differential pressurevalues of the first'and second check valves 21 and 22 are set in such amanner that when the rated amount of the oil is supplied to the solenoidvalve 14, the both check valves 21, 22 are respectively opened by thedifferential pressure higher than the inner pressure drop of the oilthrough the solenoid valve 14.

When the solenoid valve 14 is opened and the piston 3 is moved to theleft as shown in FIG. 3 at accelerated speed, the check valves 21, 22are both closed. Accordingly, the oil from the front oil chamber 10passes through the throttle device 16 only. As the piston 3; is moved tothe left as in FIG. 3, the opening ofthe throttle device 16 isincreased, whereby the flow rate of the oil therethrough is increased.When the piston 3 arrives at the left end of the bore 4, the opening ofthe throttle device 16 becomes at its maximum. At this time, thepressure differences of the oil between the pressure inlet 13 and theoil chamber 10 and between the oil chamber 7 and the oil passage 20become large enough as compared withthe set values of the check valves21, 22, so that both the check valves 21, 22 are respectively opened tosupply therethrough the oil from the pressure inlet 13 to the annularoil groove 26, whereby the acceleration of the movement of the piston 3to the left is maintainedto flow out therethrough the rated amount ofthe oil to the oil tank 18 through the oilpassages 17 and 17a.

Following thereto, if the solenoid valve 14 is closed to prevent the oilfrom being passed therethrough, the oil passes from the pressure inlet13 to the front oil chamber 10 through the first check valve 21 and theoil in the back oil chamber 7 flows out to the annular groove 26 throughthe second check valve 22. Asa result, the oil in the front oil chamberbecomes higher than that in the back oil chamber 7 to move the piston 3to the right in the figure with the result that the opening of thethrottle device 16 is decreased and accordingly the amount of the oilpassed therethrough is decreased. For this reason the moving speed ofthe piston 3 to the right becomes slow gradually and then the piston 3reaches the right end of the bore 4 is the figure to stop its movement.Thus, the acceleration and deceleration of the moving speed of thepiston 3 is carried out by the oil of a constant volume in thisinvention.

As set forth just above, according to this invention the right and leftmovements, namely the acceleration and deceleration movements of thepiston 3 are practiced by the oil or that of the constant volumeproduced by the movement of the piston 3 by a constant length,

so that the distance or range within which the piston movement isaccelerated and decelerated can be made substantially constant.Accordingly, it may be apparent that the present invention is used forhydraulic position control apparatus with high accuracy and smoothposition determination.

Further,'the example shown in FIGS. 2 and 3 can be easily assembled anddisassembled and small in size because there is employed no spring suchas shown in FIG. 1.

FIGS. 4 and 5 show still another example of this invention in whichreference numerals same to those of FIGS. 1, 2 and 3 represent the sameelements and they are substantially same in construction and operation.For this reason,'no detailed explanation will be given thereon.

In the example depicted in FIGS. 4 and 5 an oil passage 29 is providedin the body la which oil passage 29 connects the annular groove 26 withthe oil passage 17 at its middle way. In the oilpa'ssage 29 there isprovided a throttle valve such as, a needle valve 30 which can becontrolled in its opening by, for example, hand from the outside of thebody 1a. That is, the flow rate of the oil flowing through the throttlevalve 30 can be easily adjusted.

Assuming that the throttle valve 30 is entirely closed and the openingof the throttle device 16 is in proportion to the position of the piston3, the moving speed of the'piston 3, in the other words the flow rate ofthe oil passing through the acceleration and deceleration apparatus isshown in FIG. 6-by a curves a, a and a in which the abscissa representsthe time t and the ordinate the flow rate M of the oil. While, if theinitial opening of the throttle device 16 is changed, the flow rate M ofthe oil changes in time lapse within the range shown by curves a and a".For example if the initial opening of the throttle device 16 issubstantially zero, the amount M changes in accordance with the curve awith time lapse, which requires much time for acceleration.

In general, the acceleration conditions are different for respectiveposition control device, so that it may be desired that the initialopening of the throttle device 16 can be varied.

Curves b,'b' and b" in FIG. 6 show the relationship between the flowrate M of the oil and the time I when the moving speed of the piston 3is decelerated. The

curve b" shows the case where the initial opening of the throttle device16 is substantially zero while the curve b the case where the initialopening of the throttle device 16 is about maximum,

As may be apparent from the foregoing, with the embodiment shown inFIGS. 4 and 5 since the initial opening of the throttle device 16 can bechanged or adjusted by controlling the throttle valve 30, thepracticalopening of the former can be selected effectively for the devices to becontrolled in position irrespective of the initial opening of thethrottle device 16.

It will be "apparent that many modifications can be formed withoutdeparting from the concept of the novel concept of this invention.

We claim as our invention: 1. An acceleration and deceleration valveapparatus, comprising in combination:

a. a housing body (1a) having a bore (4) therein with a piston (3) insaid bore, said piston dividing said bore into fromt (l0) and back (7)chambers, bias means (2) operatively connected for biasing said piston(3), an oil chamber (8) juxtapositioned with said back chamber;

b. a tapered projection (5) on said piston extending into said backchamber and adapted to longitudinally enter said oil chamber (8);

c. a groove (15) in said oil chamber (8) towards said back chamber (7said tapered projection and groove (15) being so disposed that the sizeof the groove opening is controlled by the longitudinal position of saidtapered projection (5) so as to form a throttle (l6) and an oil passage(17) from said groove;

d. an oil pressure supply source(19), throttle means (12) between saidoil pressure supply source and said front chamber (10); and,

e. a by-pass line (14a, 14b) having a control valve (14) thereinconnected between said pressure supply source (19) and said oil chamber(8) whereby when the control valve (14) is closed, oil supplied from thepressure supply source (19) flows into the front chamber (10) to shiftthe piston (3) towards the back chamber (7) against the bias means (2)so that the projection (5) is also shifted, substantially closing thethrottle (1 6) and, when the control valve (14) is opened, oilflows tothe oil chamber (8) through control valve (14) through the throttle(16)and into the oil passage (17), the piston (3) is moved towards thefront chamber (10) by the bias means (2). I k l a 2. A valve apparatusas claimed in claim 1 where 'said bias means (2) are coiled spring meansdisposed coaxially with said piston (3) coupled thereto.

3. An apparatus as claimed in claim 1 wherein said bore and said oilchamber are cylindrical and coaxial.

4. An apparatus as claimed in claim 1 wherein said bias means (2) arefirst and second springbiased check valves (21, 22) respectively coupledto said front and back chambers.

5. An apparatus as claimed in claim 1 including a second throttleoperatively coupled to said first throttle.

6. An apparatus as claimed in claim 5 wherein said second throttle is aneedle valve. v

7. An acceleration and deceleration valve apparatus comprising a housingbody (1a) having a bore (4) therein, a piston (3) in said bore with biasmeans (2) for biasing said piston, a throttle (16) with an opening whichis controlled by said piston (3), said piston (3) dividing said boreinto front (10) and back (7 chambers, an oil passage (14a, 14b)connecting said two chambers, a'control valve (14) provided in said oilpasoil to" said oil passage and through said throttle (l6) said bore (4)and said throttle (16) being disposed in series, whereby when said valveis opened said bias means (2) operates to move said piston to onedirection to gradually open said throttle with the'movement of saidpiston, while when said valve is closed said piston is moved to theother direction by the amount of oil flowed into said valve to graduallyclose said throttle with the movement of said piston.

8. A valve apparatus as claimed in claim 7 where said bias means (2) arecoiled spring means disposed coaxially with said piston (3) coupledthereto.

9. An apparatus as claimed in claim 7 wherein said bore and-said coilchamber are cylindrical and coaxial.

10. An apparatus as claimed in claim 7 wherein said bias means (2.) arefirst and second spring biased check valves (21, 22) respectivelycoupled to said front and back chambers.

11. An apparatus as claimed in claim 7 including a second throttleoperatively coupled to said first throttle.

12. An apparatus as claimed in claim 11 wherein said second throttle isa needle valve.

1. An acceleration and deceleration valve apparatus, comprising incombination: a. a housing body (1a) having a bore (4) therein with apiston (3) in said bore, said piston dividing said bore into fromt (10)and back (7) chambers, bias means (2) operatively connected for biasingsaid piston (3), an oil chamber (8) juxtapositioned with said backchamber; b. a tapered projection (5) on said piston extending into saidback chamber and adapted to longitudinally enter said oil chamber (8);c. a groove (15) in said oil chamber (8) towards said back chamber (7),said tapered projection and groove (15) being so disposed that the sizeof the groove opening is controlled by the longitudinal position of saidtapeRed projection (5) so as to form a throttle (16) and an oil passage(17) from said groove; d. an oil pressure supply source (19), throttlemeans (12) between said oil pressure supply source and said frontchamber (10); and, e. a by-pass line (14a, 14b) having a control valve(14) therein connected between said pressure supply source (19) and saidoil chamber (8) whereby when the control valve (14) is closed, oilsupplied from the pressure supply source (19) flows into the frontchamber (10) to shift the piston (3) towards the back chamber (7)against the bias means (2) so that the projection (5) is also shifted,substantially closing the throttle (16) and, when the control valve (14)is opened, oil flows to the oil chamber (8) through control valve (14)through the throttle (16) and into the oil passage (17), the piston (3)is moved towards the front chamber (10) by the bias means (2).
 2. Avalve apparatus as claimed in claim 1 where said bias means (2) arecoiled spring means disposed coaxially with said piston (3) coupledthereto.
 3. An apparatus as claimed in claim 1 wherein said bore andsaid oil chamber are cylindrical and coaxial.
 4. An apparatus as claimedin claim 1 wherein said bias means (2) are first and second springbiased check valves (21, 22) respectively coupled to said front and backchambers.
 5. An apparatus as claimed in claim 1 including a secondthrottle operatively coupled to said first throttle.
 6. An apparatus asclaimed in claim 5 wherein said second throttle is a needle valve.
 7. Anacceleration and deceleration valve apparatus comprising a housing body(1a) having a bore (4) therein, a piston (3) in said bore with biasmeans (2) for biasing said piston, a throttle (16) with an opening whichis controlled by said piston (3), said piston (3) dividing said boreinto front (10) and back (7) chambers, an oil passage (14a, 14b)connecting said two chambers, a control valve (14) provided in said oilpassage (14a, 14b), a pressure source (19) for supplying oil to said oilpassage and through said throttle (16) said bore (4) and said throttle(16) being disposed in series, whereby when said valve is opened saidbias means (2) operates to move said piston to one direction togradually open said throttle with the movement of said piston, whilewhen said valve is closed said piston is moved to the other direction bythe amount of oil flowed into said valve to gradually close saidthrottle with the movement of said piston.
 8. A valve apparatus asclaimed in claim 7 where said bias means (2) are coiled spring meansdisposed coaxially with said piston (3) coupled thereto.
 9. An apparatusas claimed in claim 7 wherein said bore and said coil chamber arecylindrical and coaxial.
 10. An apparatus as claimed in claim 7 whereinsaid bias means (2) are first and second spring biased check valves (21,22) respectively coupled to said front and back chambers.
 11. Anapparatus as claimed in claim 7 including a second throttle operativelycoupled to said first throttle.
 12. An apparatus as claimed in claim 11wherein said second throttle is a needle valve.